You can make any object into a black hole currently, though it's not fully implemented. If you check around on the presets for the mass/density/etc, you should see the option.
Quasars aren't really fully understood currently, but they aren't really a single object to be simulated. It's an entire galactic nuclei with a combined luminosity estimated at trillions of times that of the sun.
Wiki definition: "A quasar is a compact region in the center of a massive galaxy surrounding its central supermassive black hole. Its size is 10–10,000 times the Schwarzschild radius of the black hole. The quasar is powered by an accretion disc around the black hole."
The Schwarzschild radius is essentially the point of no return for mass when it will collapse into a black hole because the escape velocity would pass the speed of light.